Piston expander



Jan. 14, 1936. L, A, W TTER 2,027,496

PISTON EXPANDER .Filed Sept. 3, 1932 mvgmon ATTORNEY Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE PISTON 'EXPANDER Leon A. Witter, Cleveland, Ohio 1 Application September 3, 1932, Serial No. 631,610

.12 Claims. (01. 309-12) This invention relates to means for expanding the split skirt of a piston. The invention contemplates the skirt as being of relatively soft metal such as an alloy of aluminum, and the principal object of the invention is to provide expanding means readily attachable to any piston of such description, and attachable if necessary, without removal of the piston from its cylinder.- l A further object of the invention is to provide that the expanding effect be applied to the piston in the zone of the wrist pin, and be adjust able in amount and yielding in character. Ehe exact nature of this invention together wi h further objects and advantages thereof will be apparent from the following description taken in connection with the accompanying drawing, in which Figs. 1 and 2 are generally longitudinal sections through a typical piston illustratingan embodiment of my invention applied thereto, the section of Fig. 1 being as in the plane of the wrist pin and the section of Fig. 2 being as indicated line 22, Fig. 1, and generally inthe plane transverseof the wrist pin; Figs. 3 and 4 are transverse sections as in the planes of lines 3-3 and 4-4 respectively, Figs. 1 and 2. With reference now to the drawing the piston shown is of conventional inexpensive design for light alloys. The principal parts of the piston are the usual head I having ring grooves 2, wrist pin bosses 3, having aligned openings 4 for a wrist pin, and a skirt 5 joined witli the wrist pin bosses. The parts are integral but the skirt 5 5 is separated from the head partof the piston by transverse slots 6 and on one side of the wrist pin bosses the skirt is split generally longitudinally as at I.

' It is the intent that the skirt be yieldablyex- 4o panded to fit the cylinder in which the piston moves, as after wear upon the piston and/or its corresponding cylinder wall, or after fatigue of the split part of the piston skirt; and my invention provides auxiliary means attachable to ex- 5 pand the piston skirt under these conditions.

Theprincipal parts of the invention are a pair of bow members 8 and 9 and means for .interassociating the medial parts thereof.

The bow member 8 has its ends I0 enlarged 0 as indicated andrecessed as at H to seatvupon the inwardly projecting parts of the wrist pin bosses}, with the bow member extending laterally from the bosses toward the split side of the piston.

5. Thebowmember 9 is longitudinally disposed,

in straddling relation with the transverse bow member 8. Its end parts [2 are wide enough to bridge the split 1 of the skirt and are shaped as indicated Fig. 2 so that one may seat in the slot 6 which separates the skirt and head parts 5 of the piston, at the end of the split 1. Preferably both ends 12 are similarly'formed so that. either may seat in the slot 6 and thus position the longitudinal bow'member substantially positively against the piston wall. 10

One or both of the bow members are of resilient materal such as spring steel, and both, are preferably of sheet metal and thus inexpensive. The medial parts of the bow members have openings to receive a bolt l3 having a nut I4 by 15 which the bows may be pulled together.v The vice is to be applied to a pist'on the nut I4 is loosened and the parts inserted to the positions 25 indicated, the transverse bow member seating against the wrist pin. bosses and the longitudinal bow member being positioned by the seating of its inner end l2 in the slot 6 of the piston. The nut I is then turned down to bring the medial parts of the bow members together. This springs the bow members, putting them under tension to exert pressure outwardly against the split side of the piston skirt. As the bow member 9 is sprung its lower end may move slightly downwardly along the piston wall. When the skirt part of the piston is thus brought up to the desired diameter the parts are securely engaged with the piston and the setting of the nut I 4 is maintained by the projecpair of wrist pin bosses and a split skirt, said .means comprising a pair of bow members one seating at its ends upon the wrist pin bosses of ward the split side of the piston, the other extending within said piston longitudinally thereof with its ends bridging the split of the piston skirt, and means interassociating the medial parts of said bow members to exert outward pressure from said bosses to said skirt.

2. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a pair of bow members one seating at its ends upon the wrist pin bossesrof the piston and extending laterally therefrom toward the split side of the piston, the other extending within said piston longitudinally there of with its ends bridging the split of the piston skirt, and means interassociating the, medial parts of said bow members to exert outward pressure from said bosses to said skirt, one of said bow members being of' spring material whereby said pressure will have a yielding characteristic.

3. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a pair of bow members one seating at its ends upon the wrist pin bosses of the piston and extending laterally therefrom toward the split side of the piston, the other extending within said piston longitudinally thereof with its ends bridging the split of the piston skirt, and means interassociating the medial parts of said bow members to exert outward pressure from said bosses to said skirt, said bow members being of spring material whereby said pressure will have a yielding characteristic.

4. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a pair of bow members one seating at its ends upon the wrist pin bosses of the piston and extending laterally therefrom toward the split side of the piston, the other extending within said piston-longitudinally thereof with its ends bridging the split of thepiston skirt, and means for adjustably interassociating the medial parts of said bow members to exert .variable outward pressure'from said bosses to said skirt.

5. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a pair of bow members one seating at its ends upon the wrist pin bosses of the piston and extending laterallytherefrom tomeans will produce outward pressure from said bosses to said skirt.

6. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a transverse bow member 5 having its ends recessed and seating upon the wrist pin bosses of the piston, with a medial part extending laterally therefrom toward the split side of the piston, -a longitudinal bow member having its ends bridging the split of 10 the piston skirt and with a medial part extending inwardly thereof, and means interessociating the medial partsof said bow members.

7. Means for expanding a piston having a pair of wristpin bosses and a split skirt, said means comprising a transverse bow member having its ends recessed and seating upon the wrist pin bosses of the piston, with a medial part extending laterally therefrom toward the split side of the piston, a longitudinal how 20 member having its ends bridging the split of the piston skirt and with a, medial part extending inwardly thereof, said bow members being arranged each straddling the other, and means connecting their media] parts and adapted to 25 adjustably pull them together.

.8. Means for expanding a piston having a pair of wrist pin bosses and a split skirt, said means comprising a transverse bow member having its ends seating upon the wrist pin 30 with one end seated in the slot at the end of said skirt, with a medial part extending inwardly, and means connecting the medial parts of said bow members.

9. Means for expanding a piston comprising a pair of bow members arranged in cruciform relation, and means interassociating their medial parts.

10. Means for expanding a piston comprising a pair of bow members arranged in cruciform relation, and means interassociating their medial parts, one of said bow members being of spring material.

11. Means for expanding a piston comprising a pair of bow members arranged in cruciform relation, and means interassociating their medial parts, said bow members being or spring material.

12. Means for expanding a piston comprising a pair of bow members arranged in cruciform relation, and means for adjustably interassociating their medial parts.

LEON A. WI'I'I'ER. 

